# US 11,298,819 B2 · Robot control method

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- Number: US 11,298,819 B2
- Document ID: US11298819B2
- Status: Granted
- Kind: B2
- Application number: 16/548,295
- Filed: 2019-08-22
- Published: 2019-12-12
- Granted: 2022-04-12
- Earliest claimed: 2017-03-01
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Hiroyuki Nakata; Atsumi Hashimoto; Ryosuke Yamamoto; Yasuyoshi Honuchi
- Web page: https://patentgrep.com/patent/US11298819B2

## CPC

- B25J 9/1628: {characterised by the control loop}
- B25J 9/1674: {characterised by safety, monitoring, diagnostic}
- B25J 9/1694: {characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion}
- H02P 21/0089: {using field weakening}
- H02P 21/22: Current control, e.g. using a current control loop
- H02P 29/62: for raising the temperature of the motor
- H02P 29/64: Controlling or determining the temperature of the winding
- B25J 9/1641: {compensation for backlash, friction, compliance, elasticity in the joints}
- G05B 2219/39192: Compensate thermal effects, expansion of links
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

A robot control method of controlling motion of a robot arm by using a servo motor includes adding d-axis electric current to a motor electric current command (steps 15-6, 15-8) if external temperature is less than or equal to a predetermined value (step 15-3), and if an absolute value of the motor electric current command is less than or equal to a predetermined value (step 15-4), and if a value of detected overload is less than or equal to a predetermined value (step 15-5).

## Claims

### Claim 1

An apparatus for controlling motion of a robot arm, the apparatus comprising:
a temperature sensor that measures a temperature; and
a servo controller that
determines whether the temperature is less than or equal to a first predetermined value,
determines whether an absolute value of a motor electric current command is less than or equal to a second predetermined value if the temperature is less than or equal to the first predetermined value,
determines whether a value of a detected overload is less than or equal to a third predetermined value if the absolute value of the motor electric current command is less than or equal to the second predetermined value, and
adds a d-axis electric current to the motor electric current command if the value of detected overload is less than or equal to the third predetermined value, and
controls the motion of the robot arm using the motor electric current command after the d-axis electric current is added to the motor electric current command.